1. Field
Embodiments described generally relate to proppants and methods for making and using same. More particularly, the embodiments relate to coated proppants containing a cured resin and methods for making and using same.
2. Description of the Related Art
The production of oil, natural gas, and other fluids from a subterranean formation can be enhanced by hydraulic fracturing. In general, hydraulic fracturing involves the injection of a fracturing fluid through a well bore and against the face of the subterranean formation to initiate new fractures and/or extend existing fractures in the subterranean formation. The fracturing fluid must be injected at a pressure and a flow rate great enough to overcome the overburden pressure, as well as to drive the fracturing of the subterranean formation.
The fracturing fluid usually contains a proppant, such as sand or gravel, which is carried into the fractures. The proppant particles become lodged in the fractures where the particles minimize or eliminate fracture reduction or closure upon reduced downhole pressures due to the removal of downhole fluids and/or a cessation in the introduction of the fracturing fluid thereto. The proppant filled fractures provide permeable channels through which the downhole fluids flow to the well bore and thereafter are withdrawn for production.
The high closure stresses applied to the proppant particles lodged in a fracture can fragment and disintegrate the proppant when the dry crush strength of the proppant is too low for the particular environment of the fracture. For example, a closure pressure of about 34.5 MPa (about 5,000 psi) or greater can disintegrate frac sand traditionally used as a proppant. The resulting fines from the crushed proppant can migrate and plug the interstitial flow passages in the remaining proppant filled fractures. These migratory fines drastically reduce the permeability of the propped fractures and therefore reduce or cease fluid production from such clogged fractures.
There is a need, therefore, for improved coated proppants that have a dry crush strength greater than traditional proppants and methods for making and using same.